Animal I have become
by missjessicapond
Summary: Katherine needed to go as far away as she could from Klaus.
1. Chapter 1

**A/N: This story is going to be placed on season 3 of TVD (when Katherine is running away from Klaus) with a few mentions of Katherine's past and also set after the last Christmas special from Doctor Who. Enjoy! :)**

The Doctor had just left the house of the Ponds, he spent Christmas with them but he couldn't stay longer that's not who he was and they knew it. After saying goodbye and promising Amy that he would come back to visit soon he entered the TARDIS.

"Where are we going now?" he asked his TARDIS walking towards the console. He barely touched the controls when abruptly the TARDIS shook and started moving. Moments later it stopped, the Doctor promptly looked at the screens and scanned the place in which it landed.

Bulgaria, June 20 1489. "Well, interesting." He turned around, his hair getting a little messy by the sudden move. "Now, what do you have for me?" he opened the door and looked outside.

He was standing in the backyard of a big house, probably owned by a wealthy family. He looked around, no sign of anything weird. He heard a noise coming from the other side of the house, he watched as a young girl stormed out of the house.

The girl couldn't be more than 14 or 15 years old. She had long brown curly hair. She was wearing a blue kirtle low front opening with laces over, it was a contemporary dress for that time but surely made of a richer fabric which showed she was the daughter of a rich family.

She stood in front of the house, right hand on her stomach while her other hand swiped the tears from her face.

The Doctor couldn't stand there and do nothing she looked deeply disturbed, he walked towards her trying not to scare her. "Are you ok? Can I help you?"

She heard a voice of a man, she turned around heart beating faster. She was scared, she had just been thrown away, rejected by her family she had nowhere else to go and there was a strange man talking to her. It was too much to take in her _condition_.

She fainted. The Doctor ran next to her, making sure she didn't hurt herself.

The Doctor was holding his sonic screwdriver, he was staring at it with a concern look on his face.

_The girl was pregnant._

He carried her into the TARDIS, making sure she'd be comfortable and he waited until she woke up.

"Oww" her head hurt, she remembered falling into ground. Her sight was still blurry, she looked around, didn't recognize the place, she blinked two more times and finally focused on the man that was sitting next to her.

"You, stay away from me!" she screamed and tried to stand up to get as far away as she could from the man but she was still weak and lost her balance.

The Doctor caught her as soon as she stood up and helped her sit again.

"You are safe here, can you trust me?" he told her sitting next to her. She looked at him, almost immediately noticing his green eyes, there was kindness in them. Maybe he really wanted to help her.

He saw her staring at him, he made sure she had time to think about the situation then he added "I'm the Doctor" and smiled kindly waiting for her answer.

"I.. I'm Katerina.. Katerina Petrova" she replied, "can you help me?"

He smiled gently at her, "of course"

She burst into tears, the Doctor hugged her. She was scared and she wanted to trust the Doctor, she knew she probably was crazy trusting a stranger but she didn't have a choice.

**A/N: Ok so this was an introduction of how the Doctor and Katherine met, next chapter I'm going to finish telling their back story and hopefully chapter 3 will be focused on the present time. So yeah, hope you stick with me :D **


	2. Chapter 2

Katerina was so young, so helpless. Just as her world crumbled under her feet he appeared. He had saved her.

The Doctor helped her find a place to stay, he stayed with her for a few days. He even managed to celebrate her birthday which was just two days after they first met. She was happy, she felt safe with him.

"So, how are you feeling?" he asked.

"I.. I feel fine" she smiled.

"Have you thought of a name?"

"No… I…" Katerina looked down. She hadn't even put a thought about the sex of her baby, things happened so fast.

"It's ok, you'll find a name, I'm sorry I asked that I know this must be difficult for you"

The Doctor put a hand on her arm trying to comfort her. He cared for her, he really did.

Two weeks had pass and Katerina was still amazed by him, he had told her about all his adventures. She wished she could go with him and see other planets, watch the stars, she loved watching the sky at night. But the Doctor had made it clear, he couldn't expose her to the dangers, she was young and she was pregnant. She couldn't really fight about it, she knew by everything he told her how dangerous could it be, he had already lost people.

-.-.-.-.-.-.-.-.-.-

It was just a matter of time, something had reclaim the Doctor's attention. He made sure she was ok before leaving. Then he promised her something.

"If you ever need me, just look at the stars, make a wish and I will come".

He didn't. It was 1492 when she wished upon the stars, she wished for him to come and save her from Niklaus.

As she hanged herself she cried, where was her friend? She had lost her daughter and she was far away from her family but after all she didn't want to die. So she became a vampire. She could forget the pain, she could turn on the switch and forget everything, forget him. She thought about it as she escaped.

When she went back to Bulgaria and found her family slaughtered something inside of her changed, she felt anger. She would never care for anyone else but herself. She would live as a vampire, she would feed as a vampire, she would become someone else, she would say goodbye to the human she once was.

-.-.-.-.-.-.-.-.-.-

Katherine had convinced Stefan to steal the coffins that contained Klaus family. She knew she had to flee. She was tired of running away, she was free for a while but then Klaus came back and she wasn't safe anymore. Even as she helped Stefan and Damon she knew they would never welcome her again. Those last months in Mystic Falls made her remember her past, every choice she had made.

She walked the streets, the moon shining above her, she stopped and looked at the sky. Then a thought crossed her mind, she remembered something that she thought she had forgotten for good. She wondered countless times if he was even real, maybe she imagined it all. Maybe she created an imaginary friend and unconsciously she had lived through the motions.

She thought of him, trying to remember the way he looked, the way he smiled and those deep green eyes.

Then suddenly something caught her attention, it was a star that started to shine brighter than the rest. She watched as the star became bigger and bigger and then she saw it… she saw the blue police box.

-.-.-.-.-.-.-.-.-.-

A/N: Short chapter! But we are getting to the interesting part ;)


	3. Chapter 3

Katherine stared at the blue box, eyes wide open. Could this be a dream? But then again… vampires don't dream.

No, this was real.

The Doctor opened the TARDIS door and there she was, Katerina.

She looked different… those clothes… he looked around and saw the buildings. This definitely weren't the 1400's. How could this be?

"It can't be" Katherine interrupted his train of thought, "you can't be here, you weren't real!" she finally screamed at him. She felt a rush of anger filling all her body.

The Doctor looked at her worried. Why was she so angry at him? He didn't understand what was happening.

"Katerina" he moved closer.

"You stay away from me. I'm not Katerina, I haven't been Katerina for almost two centuries"

"I don't understand" he watched her, somehow she looked different but he couldn't tell why.

"My name is Katherine" she barely resisted the urge to kill him. Emotions were a weakness and even so she let them in sometimes. But this time she was fighting as hard as she could, she didn't wanted to let her emotions in.

"Katerina… Katherine" the Doctor closed his eyes for a second, "what happened to you?" he asked deeply concerned.

"Why would you care now, you didn't care before" she asked with a cold voice, hands closed in fists.

"You called me before? I... I never… I'm... so sorry".

What did that mean? He didn't hear her calling? Suddenly she felt a hole inside of her, she had spent so much time thinking that he had just ignored her or that he had just forgotten about her. But she never thought that maybe… maybe… he couldn't hear her calling.

The Doctor came closer to her, "Katerina, I am truly sorry, I didn't hear you before"

Katherine closed her eyes, she let her guard down. She was allowing herself to feel.

"No," she took a step away from the Doctor. "I can't" she was almost in panic.

"Katerina…"

"Stop it! Just… stop calling me Katerina. You don't get it Doctor, I'm not the girl you knew before."

"I'm not the little helpless Katerina Petrova, she is _dead_" Katherine stood with a fierce look in her eyes, whatever emotions she let herself feel until that moment they were long gone.

"I'm Katherine Pierce, I'm not a slave of human emotions, I'm _free_" she closed her eyes and then opened them, her face changed completely. Blood rushing to her eyes, small veins protruding around them. Her teeth turned into fangs and her skin looked paler.

The Doctor stared at her, watching as she changed. He knew that she wasn't human, not anymore and he felt his hearts sinking. He didn't know how to react.

Katherine looked at him, and then in a glance she pushed him against the TARDIS, hand on his throat. She put her mouth next to his neck, almost touching it then she took a deep breath. She could tear his neck and drain him in a blink or she could have fun and torture him.

The Doctor barely saw her move, she was almost choking him. He knew what she had become, he knew that vampires could turn their emotions off. He was lost, how could he possibly survive this?

"I can't chan…ge the past" he almost couldn't talk. "You need… to feel again" He put his hands on each side of her face and closed his eyes.

Images flashed in his mind, he saw her crying and screaming as they were taking her baby away… he saw the woods, she was running… a knife piercing her skin, the taste of blood, death, darkness.

Katherine released his neck, he was still holding onto her.

Both were watching her past flashing on their minds. Tears started to fall from her eyes, she opened her mouth in pain. Her face looked normal again.

The Doctor felt her pain. He hated himself for forcing her to relive her past but it was the only way to make her feel again.

They saw the last image disappear. Both opened their eyes at the same time. He took his hands away from her face. She was shaking, crying.

The Doctor rested his hands on her shoulders.

She was overwhelmed by all the feelings. As soon as she felt the Doctor's hands on her shoulders she gave up and rested her head on his chest, her hands clenched on his jacket.

She was exhausted. The Doctor held on to her tightly.

"Take me with you" she whispered at him, "please..." her voice cracked.

He smiled gently, he took her hand, Katherine wiped the tears off with the other hand as they entered the TARDIS.

-.-.-.-.-.-.-.-

A/N: Turned out a bit fluffy, that's ok. Katherine might look a little OOC at the moment but there's still a couple of chapters to come so who knows what might happen? *winks*


	4. Chapter 4

**A/N: Ok.. I have no idea where this came from but here's the final chapter.**

Katherine was having so much fun with the Doctor. She saw the stars, she could almost touch them and yet there was something that she couldn't let go… Klaus.

Why couldn't she forget about him? She didn't have to fear him anymore, but she was worried about Damon and Stefan, she knew he was still threatening them. She hated to admit that she cared, maybe too much.

It was just a matter of time before the Doctor asked, "where do you want to go?" and she saw an opportunity. She could make him suffer, she could change the past. She knew that the Doctor would never let her do it, but she had a plan.

"I… I would like to see my daughter… can you take me to her?"

"Katherine… I don't know, it's dangerous…"

"Please, Doctor" He knew how she felt, losing someone and then have an opportunity to see them again, he couldn't refuse.

"Ok, but you have to promise that you won't tell her who you are or change anything on her life while we are there"

"I promise" Katherine hugged him, she closed her eyes for a moment. It was time.

The TARDIS appeared in the street. Katherine and the Doctor walked towards a house, it was a nice place, looked like her daughter was adopted by a good family.

Katherine almost felt the urge to run away. No, she had to do this...

A little girl was playing on the backyard, she must have been 8 years old. She looked so much like her, Katherine approached her. The Doctor waited and watched Katherine as she got closer to her daughter.

Her heart was beating faster, she had her eyes.

"Hi" she waved at the girl.

The girl looked at the woman, "I shouldn't talk to strangers" she said with the sweetest voice and Katherine felt a hole in her chest.

"It's ok, I… just want to know… are you happy?"

The girl looked at her and frowned, "yes" she answered.

She was happy. That's all she needed to know.

Katherine's face changed, the little girl screamed.

The Doctor ran towards Katherine.

"What are you doing! Katherine" he took her arm, she had transformed.

"Get out of my way"

"Im sorry Katherine I can't let you do this" he had figured out what she wanted to do, all this time she played with him when everything she wanted was revenge. Katherine was right about something, she wasn't the girl he knew. He had to accept that she was a vampire and she would never have her human emotions restored completely. He knew that… and this time he was prepared.

Katherine felt her skin burning, the Doctor held her as she lost her balance. "Vervain…" Katherine glanced at him and then fainted. He had injected her with Vervain.

He made sure Katherine's daughter was ok before leaving.

The TARDIS arrived on earth, year 2012.

Katherine was almost completely recovered, she hadn't spoken with the Doctor since the incident but she knew that he was taking her back.

At first he felt angry at her and then he felt sorry. She would never be Katerina again and he couldn't help her not after what she did.

She let the emotions in and out. Almost losing herself in the process, she was confused, angry, sad. She was broken.

"Goodbye Katherine" the Doctor watched her walk outside the TARDIS.

She turned around, she felt empty inside. She knew he could never forgive her betrayal, she knew she had lost him forever.

Katherine approached the Doctor and kissed him in the cheek.

"Goodbye" she whispered to him and then walked away.

She was feeling numb, it was just when she heard the TARDIS leaving that it hit her. Her hands covered her mouth as she cried.

The Doctor stood in front of the door, the kiss she gave him made him realize how he felt about her. He almost came back for her but he resisted. However, there was something he could do for her, one last thing.

Katherine spent days without leaving the room of the hotel. She had spoken with Damon and she knew that Klaus was still busy trying to find the coffins. She decided she could herself a break and just stay in a place for a while.

Someone knocked at the door.

There was no one outside, she looked in the hall confused then she glanced at the floor. There was a box with a note on it.

"I think you will find this useful – The Doctor" she almost let the note fall when she read the signature.

She took the box and opened it.

He had found a weapon that could kill Klaus. Another little note inside said "This is called the Colt, kills any supernatural being – be careful!"

Katherine took the gun in her hands.

"Thank you Doctor"

**A/N: Little wink at a possible Supernatural crossover in there LOL. I just... I don't know, I feel like I lost track of where I wanted to go with this final chapter. I've just been so busy with life that I can barely think straight. Anyway, hope you liked it. And hopefully more people will start writing Katherine/Eleven *winks* **


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